Heater control



Dec. 1, 1931. BARKER I 1,833,888

HEATER CONTROL Filed June 15. 1929 4 Sheets-Sheet 1 G. D. BARKER Dec. 1, 1931.

HEATER CONTROL 4 Sheets-Sheet 2 I mmmmm Filed June 15 129 Dec. l, 1931.

G. D. BARKER HEATER CONTROL Filed June 15, 1929,

4 Sheets-Sheet 3 5' FIG. 5

1931- G. D BARKER 1,833,888

HEATER CONTROL I Filed June 15, 1929 4 Sheets-Sheet 4v FIG- 7 Fl 6. gjwuwntor,

Patented Dec. 1, 1931 UNITED STATES GALEN' I). BARKER, OF DOWAGIAC, MICHIGAN HEATER CONTROL Application filed June 15,

This invention relates in general to controls for heaters, and more particularly to a furnace or boiler control utilizing damper mechanism for regulating the combustion.

One of the principal objects of the present invention is to provide a device of this character which so regulates the draft through the furnace as to prevent the fire from going out completely when banked and yet preclude 3a excessive acceleration of combustion when the draft through the fire is being sustained and also prevent cold air from passing through the fire box and through the heater and carrying the heat up the stack when the fire is checked.

Another object of the invention resides in the provision of a control of this character and having these advantages and which is of simple and durable construction, reliable as and effective in operation, and easy and comparatively inexpensive to manufacture and install.

in carrying out the present invention a novel damper mechanism is provided and is adapted for use alone or for organization with suitable controls. The damper mechanism includes a statically balanced check draft damper eccentrically pivoted so as to be responsive to the draft through the stack and to tend to open under the influence of such draft. The checkdraft damper is biased to closed position by an adjustable overbalancing weight which may be accurately setto determine the point at which the check draft damper opens in response to the pull of the draft through the stack. When a direct draft damper is employed it is embodied in the ash pit and is of the same construction as the check draft damper. The direct draft damper is controlled solely by the draft and as the draft is regulated by the automatic action of the check draft damper, the check draft damper indirectly controls the directdraft damper.

Under many circumstances it is desirable to sustain accelerated combustion over a considerable period after the draft has reached the point Where it will be effective to open the check draft damper against the action of its biasing weight and thus retard the com- 1929., Serial No. 371,074.

bustion. In order to provide for sustained acceleration of combustion notwithstanding the tendency of the draft to open the check draft damper, auxiliary means is provided for yieldably holding the check draft damper 55 closed or, in other words, for additionally biasing the same to closed position. This auxiliary control means may take various forms but usually it comprises an arm brought into the path of a projection on the check draft damper and tending to hold the same closed. The means for bringing the arm into the path of projection on the check draft damper may be manual or may comprise a room thermostat or other thermostatic switch which controls the operation of an electric or other type of motor connected to the mounting of the arm or which controls the excitation of an electromagnet, the armature of which carries the arm. The arm is either inherently resilient or else so mounted as to apply a yieldable bias to the projection of the damper thus permitting the damper to open if the draft through the stack exceeds the maximum point at which the heater can open ate with safety or efficiency.

Other objects and advantages reside in certain novel features of the construction, arrangement and combination of parts which will be hereinafter more fully described and particularly pointed out in the appended claims, reference being had to the accompany ing drawings, forming a part of this specification, and in which:

Figure 1 is a view in elevation showing a furnace equipped with a control system embodying the present invention;

Figure 2 is a fragmentary View in elevation on an enlarged scale and showing the check draft damper and its controls, the easing enclosing the electromagnetic control for the check draft damper being shown in section for the sake of illustration;

Figure 3 is a view of the check draft damper positioned as shown in Figure 2, the smoke pipe or stack being shown in section to illustrate the construction of the check draft damper and parts carried thereby;

Figure 4 is a fragmentary view similar to taken on line 77 of Figure 8;

Figure 8 is a detail view in elevation of the carrier for the armature and arm and associated'parts, one of the carrier plates being removed and parts being shown in section for the sake of illustration; 7

Figure 9 is a fragmentary View in elevation showing a modified form of auxlhary control for the check draft damper;

Figure 10 is a view in vertical section taken on line 10-10 of Figure 9; and

Figure 11 is a diagrammatic view showing one way of connecting the room thermostat in circuit with the windings of the electromagnet.

Referring to the drawings, the numeral 1 designates a heating plant which may be of any conventional or known type, such as a hot air furnace, a hot water, steam or vapor boiler, a gas fired furnace or an oil fired furnace. The present invention is adapted for use on any of the various types of heating plants.

The stack or smoke pipe of the furnace is designated at 2 and is provided with a flanged opening 3 controlled by a check draft damper designated generally at 4. In order that the force of the draft may be eflective to tend to open the damper 4 it is eccentrically pivoted upon the wall of the flanged or reinforced opening 3 by means of opposite trunnions 5 (see Figures 3 and 5). With such a mounting the portion or section of "the damper below the trunnions or pivots 5 is of larger area than the portion above such pivots and the consequent differential permits the draft to tend to draw or suck the lower portion inwardly while the upper portion swings outwardly as shown in Figure 3. I The eccentric mounting of the damper disturbs its static balance and in order to restore this static balance the upper portion of the damper is symmetrically enlarged or weighted as shown at 6.. i

The present invention proposes to'provide the damper 4 with an adjustable bias which holds it in closed position until the draft reaches a predetermined point or value. This adjustable bias is obtained by means of an adjustable overbalancing weight 7, the weight 7 being fixed to the inner end of a screw 8 supported for longitudinal adjustment in a bearing or opening 9 provided in the damper 1 and so located that the longitudinal axis of the screw intersects the axis of swing ofthe damper and is located in all adjustments in a plane at right angles'to the plane of the damper. A nut 10 is thrcadedly engaged with the screw 8 and bears on the boss 9 projecting beyond the outer face of the damper 4 around the opening 9. Whlle the screw may be rotated it is frictionally held in any adjustedposition and is also secured against longitudinal movement by means of a flat spring 11 having a portion secured as at 12 to the damper 4 and an offset 'portion 13 bearing flatly against the outer face of the nut. Preferably, the screw has a longitudinally extending flat 8 against which the end of the spring 11 bears so as to prevent the screw from turning while leaving it free for axial or longitudinal adjustment. When the damper 4 is swung to closed position under the action of its overbalancing or biasing weight 7 its lower portion engages a stop pin 15 provided on the flange 3.

Under some conditions it may be adjusted to utilize a check draft damper of this character independently of any additional controls and independently of any direct draft damper.

In the furnace illustrated, however, a direct draft damper 1G is mounted in the ash pit door and is of the same construction as the damper 4, the damper 16 being weighted as at 6 to restore its static balance and having an adjustable overbalancing or biasing weight 7 similar to the Weight 7 and adjusted by the same type of screw and nut, designated at 8 and 10, respectively, a spring 11 coacting with the nut 10' and screw 8 operating to maintain the adjustment of the Weight the damper 4, if desired.

When the combustion in the furnace is being accelerated, the draft through the fire and up through the stack increases. At first, under such circumstances, the direct draft damper 16 is open and the check draft damper 4 closed. However, when the draft in the stack has increased up to a predetermined point or value, it sucks the check draft damper 4 open notwithstanding the action of its biasing weight 7 and thereby reduces the amount of air pulled through the fire and drawn past the direct draft damper. Consequently the direct draft damper closes and combustion is retarded. As soon as the draft in the stack slows down, the check draft damper 4 closes thereby causing the stack draft to increase and consequently the direct draft damper to. open so as to again accelerate combustion. This .automatic action is repeated over and over to maintain the fire burning properly. The point at which. the draft in the stack will open the check draft damper is determined by the adj ustment of its overbalancing or biasing weight 7. The check draft damper 4, through its effect on the draft, indirectly controls the direct draft damper 16 but the responsiveness of the direct draft damper 16 to this control is determined by the adjustment of its b-iasing weight 7 a Apart from any additional controls such dampers (the dampers 4 and 16) may be used with advantage under many conditions and, of course, as indicated above, the check draft damper 4 may be used alone.

In many instances, however, it is desirable to have the acceleration of the combustion in the boiler or furnace maintained even after the draft in the stack has increased to or beyond the point at which it would be effective to open the check draft damper 4 against the action of its biasing weight 7. Thus, where the boiler or furnace is associated with a heating system there is considerable lag between the acceleration of the combustion and the rise in temperature in the heating medium, or of the room temperature. Frequently, rapid or accelerated combustion must be sustained over a considerable period to bring the temperature of the heating medium or the room temperature up to the desired point.

In order to provide for sustained acceleration of combustion and yet preclude combustion from progressing beyond the point where the heat generated can be utilized with safety and efficiency in the system, the check draft damper 4 may be further regulated in its action by means of an auxiliary control.

One type of auxiliary control is shown in Figures 2, 4. 5, 7 and 8 and comprises an electromagnet 20 supported in a casing 21 provided alongside the flanged opening 3. The excitation of the windings of the magnet 20 is controlled by an ordinary room thermostat 22', the terminals of the windings 20 of the magnet being connected in circuit with the thermostatic switch of the room thermostat, as illustrated in Figure 11 or in any appropriate manner. An armature 22 of laminated iron is secured between carrier pates 23 of insulating material by means of bolts and nuts 24. The plates 23 are pivotally or rockably supported on a supporting pin 25 extending loosely through openings in the plates and secured to a boss 21 formed on the back wall of the casing 21. The armature 22 is curved slightly so that in one position its ends lie in close proximity to the pole pieces 20 of the electromagnet. A yieldable arm 26 which may be of flat resilient metal has one end wrapped around and soldered or otherwisesecured to a screw or bolt 27 extending between and fastened to the plates 21 at one corner of the carrier and has its other end weighted as indicated at 28. The weight 28 and the weight of the arm 26 biases the armature to the position shown in Figure 2 wherein its ends are moved a slight distance away from the pole pieces of the magnet. As shown in the drawings, the arm 26 extends through a slot in the casing 21 and projects into adjacent proximity to the damper 4. A pin or projection 29 is secured to the damper 4 along the line of its axis of rotation and has an offset outer end 29 adapted to be engaged by the yieldable arm 26 when the yieldable arm-26 is rocked up from the position shown in Figure 2 to the position shown in Figure 4. It is obvious that the plates 23 and their connecting parts constitute a shiftable support or shiftable carrier for the biasing arm 26 and that shifting of the support controls the coaction of the biasing arm with the damper. The arm 26 is swung to the position shown in Figure 4 whenever the magnet 20 is energized. Excitation of the magnet will attract the ends of the armature 22 into close proximity to thepole pieces and in so doing will rock the armature and its carrier and consequently rock the arm 26. When the room thermostat calls for heat its contacts will complete the electrical circuit in which the windings of the armature are incorporated thereby exciting the magnet and positioning the arm in engagement with the projection 29, When the arm 26 engages the projection 29 it tends to hold the check draft damper 4 closed and any opening of the damper at such time is against not only the action of its biasing'weight 7 but also against the yieldable resistance afforded by tion beyond the point where the heat generated can be absorbed with safety and efficiency in the system the increased suction on the damper 4 will cause it to swing inwardly, the arm 26 flexing under the pressure of the projection 29 to permit of the opening of the damper 4. This maintains the amount of air pulled through the fire at the desired value. When the temperature of the room rises to the selected point the room thermostat breaks the circuit in which the electromagnet is incorporated and the arm 26 drops down to the position shown in Figure 2, in which position the draft must overcome merely the force of the biasing weight 7 to effect opening of the check draft damper. Under such circumstances the direct draft damper eventually closes.

The rockable carrier on which the armature of the electromagnet is supported is provided with a bracket 50 which has a clip 51 secured thereto. A mercury switch 52 is held in the clip 51. As this mercury switch 52 is operated under the control of the room thermostat 22 it may be connected by wires 53 with the control circuits of auxiliary equipment such such control circuits and thereby regulate the action of such auxiliary equipment;

In the form of the invention shown in- Figures 9 and 10 a different form of auxiliary control is illustrated and employs an arm 30 pivotally supported as at 31 on a bracket 32 carried by a vertically adjustable support 33. The arm 30 is biased to the position shown in Figure 7, wherein it rests on a stop pin 34, by means of an adjustable weight 35 threaded on the arm and held in adjustable position by a set screw 36. The arm 30 extends into the path of projection 29 on the damper 4. The support 33 is preferably in the form of a strap or bar and has longitudinal slots 37 through which screws 38 extend, the screws being threaded into a supporting block 39 fastened to the flanged opening of the smoke pipe or stack. These screws 38 and slots 37 constitute a guide for constraining the support 33 to vertical movement and the ends of the slots are engageable with the screws to limit the vertical adjustment of the sup- "port in either direction. When the support 33 is pulled upwardly as far as it may be the arm 30 is brought into engagement with the projection 29 of the damper 4 and exerts a yieldable biasing action thereon just as the arm 26 of the electromagnetic auxiliary control did in the other embodiment of the invention. Thus, the arm 30, biased as it is by its weight 35, supplements the action of the weight 7 in biasing the damper'4 to closed position. The adjustment of the support 33 can be carried out in a number of ways. Obviously it is feasible to manually raise and lower this support as, for instance, by connecting a chain to the support and extending it over suitable pulleys to a control station located on one of the upper floors of the building in a household installation. Some form 'of releasable means coacts withthe chain in a position to retain the support 33 elevated. Such a chain andxpulleys are at present used in many instances to inan'uallycontrol the ordinary types of direct 1 draft dampers and check draft dampers.

The present invention preferably provides an automatic means for raising and lowerlng the support 33 and this means may consist of a chain 40 having one end connected through a spring 41 through the upper end of the support 33 and having its other end connected to a crank 42 and fixed to a shaft 42 driven by an electric motor 43, the intermediate portion of the chain being trained over the pulleys 44. The electric motor is controlled from room thermostat 45 of conventional construction been used for controlling the ordinary types with the pro ection 29. When the room tem- .perature has risento the desired point the room thermostat again causes operation of the motor 43 to rotate the crank 42 back to the position shown in Figure 7 which permits the adjustable support 33 to lower 'under the action of a weight 46 suspended thereon and relieves the damper 4 of the additional bias exerted through the weighted arm 30.

Obviously, the shiftable support 33 may be utilized to tilt a mercury switch carried by a suitable supporting bracket on the stack pipe, such a mercury switch being similar to the mercury switch 53 shown in Figure 2 and also being mounted on a separate rockable support and being employed for controlling the making and breaking of circuits in auxiliary equipment. 7

In connection with both forms of the invention it is to be understood that in most instances it is necessary to employ an auxiliary control in the form of a yieldable arm such as 26 in Figures 1 and 5, and 30 in Figures 9 and 10, this yieldable arm being motor operated and tending not only to apply an additional bias to the check draft damper, as above pointed out, but also operating when the room thermostat calls for heat to close the check draft damper should the same be open. In this way when a rise in temperature is desired the check draft damper is closed under the action of the auxiliary control and acceleration of combustion follows.

The invention claimed is:

1. A control for heaters including a dam per, means for swingably supporting the damper so that the draft tends to open the same, and an adjustable overbalance tending'to bias the damper to closed position and comprising a weight, a screw carrying said weight, a bearing for said screw having its axis in a plane at right angles to the plane of the damper and intersecting the axis of swing of the damper, a nut threadedly engaged with the screw, and means coacting with the screw and nut to constrain the nut to rotary and the screw to axial movement and to releasably hold the nut in any angular adjustment.

2. A device for controlling the operation of a heating plant having a check opening.

in the stack and comprising a check draft damper, means for supporting said damper in said opening whereby the draft tends to the same while permitting the damper to open when the draft in the stack exceeds a predetermined maximum, and a direct draft damper opened and closed automatically in response to draft conditions created by the check draft damper.

' 3. A device for controlling the operation of a heating plant having a check draft damper and comprising means for supporting the damper whereby the draft tends to open the same, an adjustable overbalance carried by the damper and tending to close the same, and an auxiliary control operable to apply an additional yielding bias on the damper to tend to close the same.

4. A device for controlling the operation of a heating plant having a damper, means for supporting the damper so that the draft tends to open the same, an adjustable overbalance carried by the damper and tending to close the same, an additional yieldable biasing member for said damper, means for shifting said yieldable biasing member into and out of operative relation with respect to said damper, and a room thermostat for controlling the shifting of said yieldable biasing member. I

5. A device for controlling the operation of a heating plant comprising a damper, means for supporting the damper so that the draft tends to open the same, an adjustable overbalance connected to' the damper and tending to bias the same to closed position, elec'trom'agnetically operated means operable when energized to apply an additional bias to the damper to tend to hold the same closed and when de-energized freeing the damper of the additional bias, and a room thermostat controlling the excitation of said electromagnetic means.

v 6. A device for controlling the operation of a heating plant including a damper, means for supporting the damper so that the draft tends to open the same, an adjustable over balance biasing the damper to closed position, a shiftable support, means for shifting,

said support, an arm carried by said support and adapted in one position of the sup port to coact with the damper to apply an additional bias thereto tending to hold the damper closed.

7. A device for controlling the operation of a heating plant including a damper, means for supporting the damper so that the draft tends to open the same, an adjustable overbalance biasing the damper to closed position, a shiftable support, means for shifting said support, an arm carried by said support and adapted in one position of the support to coact with the damper to apply an additional bias thereto tending to hold the damp- 1 er closed, and room thermostat controlled means for shifting said support.

8. A device for controlling the operation of a heating plant comprising a damper adapted to be opened by the force of the draft, means for biasing the damper to closed position, an electromagnet for operating said biasing means and a room thermostat controlling the operation of said magnet.

9. A device for controlling the operation of a heating plant including a damper adapted to be opened by the draft, a biasing arm, a member on said damper engageable with said biasing arm, an electromagnet having its armature connected to said biasing arm and controlling its engagement with the member of the damper, and a thermostatic switch controlling the excitation of the magnet.

10. A device for controlling the operation of a heating plant comprising a damper adapted to be opened by the force of the draft, shiftable means for biasing the damper to closed position, electrically operated mechanism for shifting said means into and out of cooperative relation with respect to the damper and a thermostatic switch for regulating the action of said electrically operated mechanism.

11. A device for controlling the operation of a heating plant comprising a damper adapted to be opened by the force of the draft,

yieldable means for biasing the damper to closed position, a shiftable support for said yieldable means and operating to regulate the coaction of said yieldable means with the damper, and means for shifting said shiftable support.

12. A device for controlling the operation of a heating plant comprising a damper sup ported so as to be adapted to be opened by the force of the draft, a shiftable biasing element adapted to cooperate with the damper to bias the same to closed position, and electrically operated mechanism for shifting said element.

13. A device for controlling the operation of a heating plant comprising a damper supported so as to be adapted to be opened by the force of the draft, electromagnetic means yieldably biasing the damper to closed position and temperature controlled means for regulating the action of the electromagnetic means.

In witness whereof, I hereto aflix my sig- 

